Hip dysplasia is associated with abnormal joint structure and a laxity of the muscles, connective tissue, and ligaments that would normally support the joint. As joint laxity develops, the articular surfaces of the two bones lose contact with each other. This separation of the two bones within the joint is called a subluxation, and this causes a drastic change in the size and shape of the articular surfaces. Most dysplastic dogs are born with normal hips but due to their genetic make-up (and possibly other factors) the soft tissues that surround the joint develop abnormally causing the subluxation. It is this subluxation and the remodeling of the hip that leads to the symptoms we associate with this disease. Hip dysplasia may or may not be bilateral; affecting both the right and/or left hip.

The diagnosis of canine hip dysplasia is typically made by combining: clinical signs of arthritis and pain, a complete physical exam, and radiographs (x-rays). If a dog is showing outward signs of arthritis, there are usually easily recognized changes in the joint that can be seen on radiographs. In addition, the veterinarian may even be able to feel looseness in the joint or may be able to elicit pain through extension and flexion of the rear leg. Regardless, the results are straightforward and usually not difficult to interpret.
Hip dysplasia is a widespread condition that primarily affects large and giant breeds of dogs. There is a strong genetic link between parents that have hip dysplasia and the incidence in their offspring. There are probably other factors that contribute to the severity of the disease like wrong diet, intensive effort of young dogs.